STANDARDS

Interfaces documented on this reference page conform to industry
standards as follows:

frexp(): XPG4

ldexp(): XPG4

logb(): XPG4-UNIX

scalb(): XPG4-UNIX

Refer to the standards(5) reference page for more information
about industry standards and associated tags.

DESCRIPTION

Every nonzero number can be written uniquely as the normalized mantissa
(fraction) z times 2 raised to
the power p, where the absolute value of
z is in the range [0.5, 1.0), and the exponent p, is an integer.

The frexp() and frexpf() functions
break a floating-point number into a
normalized fraction and an integral power of 2. The functions store the
integer in the int object pointed to by the n parameter and
return the fraction part.

The ldexp() and ldexpf() functions
multiply a floating-point number, y, by an integral power of 2.

The logb() and logbf() functions return a signed integer
converted to double-precision floating-point and so chosen that
1 <= |x|/2**n < 2 unless x = 0
or |x| = infinity or x
lies between 0 and the Underflow Threshold.